4 oo BOTANY OF THE LIVING PLANT 



others there is a pair of nuclei, or only one. These septate Fungi are 

 sometimes called Eumycetes. The sexual organs of many of them 

 show a resemblance to those of Red Algae, especially when there is 

 a female oogonium with trichogyne. But in many of them such organs 

 of sex have not been found, and there is reason to believe that they 

 are no longer sexually produced. They are divided into two sub- 

 classes, according to the method of production of their spores. In 



Fig. 298. 



Portion of the hymen ium of the Morel 

 {Morchella esculenta). a =asci, each con- 

 taining eight ascospores. p = paraphyses. 

 sh = subhymenial tissue. ( x 240.) (After 

 Strasburger.) 



Fig. 299. 



Honey Agaric (Ar miliaria mellea). A, 

 young basidium with two primary nuclei. 

 P^ after fusion of the two nuclei. C =*a 

 basidium of Hypholoma appendiculatum 

 before the four nuclei derived from the 

 secondary nucleus of the basidium have 

 passed into the four basidiospores 

 D = passage of a nucleus into the basidio- 

 spore. (After Ruhland.) (From Stras- 

 burger.) 



the first the spores are commonly eight in number, and are produced 

 internally within a closed body, the ascus. These are called ascospores, 

 and the sub-class the Ascomycetes (Fig. 298). To them belong 

 many Moulds, Ergot of Rye, the edible Truffle, etc. Examples will 

 be described in Chapter XXVI. 



In the second sub-class the spores are produced externally, com- 

 monly to the number of four, upon a body called a basidium. They 

 are called basidiospores, and the sub-class the Basidiomycetes 

 (Fig. 299). To them belong the Mushrooms and Puff-balls ; also the 

 large series of parasitic Rusts, which being more primitive in their 

 characters than the rest, give probable clues to the origin of the 

 Basidiomycetes. They will be described in Chapter XXVII. Both 

 the ascospores and the basidiospores are to be held as equivalent to 



